Light-emitting diode die package and method for producing same

ABSTRACT

The present invention relates to a light-emitting diode die package having an LED die and an accommodating housing. The LED die has a first doped layer doped with a p- or n-type dopant and a second doped layer doped with a different dopant from that doped in the first doped layer. Each of the first and second doped layers has an electrode-forming surface formed with an electrode, on which an insulation layer is formed. The insulation layer is formed with exposure holes for exposing the electrodes corresponding thereto. Each of the exposure holes is formed inside with an electrically conductive linker. The accommodating housing has an open end through which an accommodating space is accessible. The LED die is positioned within the accommodating space in such a manner that the electrically conductive linker protrudes outwardly from the accommodating space.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. Ser. No.12/700,062, filed Feb. 4, 2010, now U.S. Pat. No. 8,242,517 thedisclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a light-emitting diode (LED) diepackage and a method for producing the same, and more particularly, toan LED die package and a method for producing the same with a reducedbin number.

2. Description of the Prior Art

FIG. 8 is a schematic side view of a conventional LED package. FIG. 9 isa schematic diagram showing a bin distribution of LED chips afterpackaging, in which the light emitted from the LED chips have the samewavelength and the same brightness.

Referring to FIG. 8, the conventional LED package includes an LED chip91 disposed on a lead frame 90, and a lens 92 formed on the lead frame90 in a manner covering the LED chip 91.

The electrodes (not shown) of the LED chip 91 are connected electricallyto the corresponding legs 900 of the lead frame 90 via wires 93.

It should be noted that a phosphor layer 94 is formed on anelectrode-side surface of the LED chip 91. The formation of the layer 94is achieved by the following steps: coating the electrode-side surfaceof the LED chip 91 with liquid phosphor layer material and curing theliquid phosphor layer material by a baking process so as to form thephosphor layer 94.

However, the convention process for formation of the phosphor layer 94has the following drawbacks:

1. Uneven thickness—flowing of the liquid phosphor layer material in alldirections may occur before performing the baking process and,therefore, the respective phosphor layers 94 formed on the respectiveLED chips 91 will differ in thickness.

2. Different area—due to the same reason as mentioned in point 1 above,the areas of the respective phosphor layers 94 formed on the respectiveLED chips 91 will be different.

3. Different shape—due to the same reason as mentioned in point 1 above,the respective phosphor layers 94 formed on the respective LED chips 91will differ in shape.

4. Relative position offset—due to the same reason as mentioned in point1 above, the positions of the respective phosphor layers 94 formed onthe respective LED chips 91 relative to the corresponding LED chips 91will be different.

Due to the aforesaid drawbacks, the LED chips which originally emitlight with the same wavelength and the same brightness would beunfavorably fabricated into LED chip packages that show a broad varietyin terms of color temperature, brightness and wavelength, resulting inthe so-called side bins. Referring to FIG. 9 that shows a bindistribution resulted from the drawbacks described above, it should benoted that the LED chips sorted into the same bin will be divided into128 bins after the packaging process. Normally, only the central 60% ofthe packages in the distribution are adapted for subsequent use, and therest 40% are considered as side bins. As a result, the manufacture costis increased.

Moreover, since the cross-sectional area of the wire 93 is so small thatthe heat generated by the LED chip 91 can hardly dissipate to thesurroundings through the legs 900 of the lead frame 90, the heat wouldconsequently reduce the efficiency of the LED chip package.

In view of the above, the inventor has devised an LED die package, aswell as a method for producing the same, to fulfill the need in thisrespect.

SUMMARY OF THE INVENTION

Accordingly, an object of the invention is to provide an LED die packageand a method for producing the same.

In order to achieve this object, a light-emitting diode die packageaccording to a technical feature of the invention is provided, whichcomprises a light-emitting diode die and a generally basin-shapedrectangular accommodating housing. The light-emitting diode die has afirst doped layer doped with a p- or n-type dopant and a second dopedlayer doped with a different dopant from that doped in the first dopedlayer and disposed on the first doped layer. Each of the second dopedlayer and the first doped layer has an electrode-forming surface formedwith an electrode, on which an insulation layer is formed. Theinsulation layer is formed with a plurality of exposure holes forexposing the electrodes corresponding thereto. Each of the exposureholes is formed inside with an electrically conductive linker forelectrically connecting the electrodes to external circuit components.The accommodating housing is made of an insulative transparent materialdoped with phosphor powder and has an open end through which anaccommodating space is accessible. The light-emitting diode die ispositioned within the accommodating space of the housing in such amanner that the electrically conductive linker protrudes outwardly fromthe accommodating space.

According to another technical feature of the invention, a method forproducing a light-emitting diode die package is provided, whichcomprises providing at least one light-emitting diode die which has afirst doped layer doped with a p- or n-type dopant and a second dopedlayer doped with a different dopant from that doped in the first dopedlayer and disposed on the first doped layer, wherein each of the seconddoped layer and the first doped layer has an electrode-forming surfaceformed with an electrode, on which an insulation layer is formed, andwherein the insulation layer is formed with a plurality of exposureholes for exposing the electrodes corresponding thereto, and whereineach of the exposure holes is formed inside with an electricallyconductive linker for electrically connecting the electrodes to externalcircuit components; and providing a generally basin-shaped rectangularaccommodating housing made of an insulative transparent material dopedwith phosphor powder, the housing having an open end through which aplurality of accommodating spaces are accessible, wherein thelight-emitting diode die is positioned within the correspondingaccommodating space of the housing in such a manner that theelectrically conductive linker protrudes outwardly from theaccommodating space; and subjecting the housing to a dicing process, soas to obtain an individual light-emitting diode die package.

According to still another technical feature of the invention, alight-emitting diode die package is provided, which comprises alight-emitting diode die having a first doped layer doped with a p- orn-type dopant and a second doped layer doped with a different dopantfrom that doped in the first doped layer and disposed on the first dopedlayer, wherein each of the second doped layer and the first doped layerhas an electrode-forming surface formed with an electrode, on which abuffer layer is formed, and wherein the buffer layer is formed with aplurality of through holes for exposing the electrodes correspondingthereto; an insulation layer formed on the buffer layer, wherein theinsulation layer is formed with a plurality of exposure holes, eachbeing registered with the through holes corresponding thereto, and atleast one via hole for exposing a portion of the buffer layer that isexposed by the through holes, and wherein the through holes and theexposure holes are each formed inside with an electrically conductivelinker; and a generally basin-shaped rectangular accommodating housingmade of an insulative transparent material doped with phosphor powder,the housing having an open end through which an accommodating space isaccessible, wherein the light-emitting diode die is positioned withinthe accommodating space of the housing in such a manner that theelectrically conductive linker protrudes outwardly from theaccommodating space.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and effects of the invention willbecome apparent with reference to the following description of thepreferred embodiments taken in conjunction with the accompanyingdrawings, in which:

FIGS. 1-6 are schematic diagrams illustrating a method for producing anLED die package according to a preferred embodiment of the invention;

FIG. 7 is a schematic top partial view of a printed circuit board onwhich an LED die package provided with a plurality of LED dies ismounted;

FIG. 8 is a schematic side view of a conventional LED package;

FIG. 9 is a schematic diagram showing a bin distribution of LED chipsafter packaging, in which the light emitted from the LED chips have thesame wavelength and the same brightness; and

FIG. 10 is a schematic cross-sectional view of an LED die packageaccording to another preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before the present invention is described in greater detail, it shouldbe noted that the same or like elements are denoted by the samereference numerals throughout the disclosure. Moreover, the elementsshown in the drawings are not illustrated in actual scale, but areexpressly illustrated to explain in an intuitive manner the technicalfeature of the invention disclosed herein.

FIGS. 1-6 are schematic diagrams illustrating a method for producing anLED die package according to a preferred embodiment of the invention.

Referring to FIGS. 1-6, a plurality of light-emitting diode (LED) diesare first provided, each having a first doped layer 10 doped with a p-or n-type dopant and a second doped layer 11 doped with a differentdopant from that doped in the first doped layer 10 and disposed on thefirst doped layer 10 (For illustrative purpose, FIG. 1 only shows asingle LED die).

The second doped layer 11 and the first doped layer 10 haveelectrode-forming surfaces 110,100 formed with electrodes 111,101, onwhich an insulation layer 12 is formed. The insulation layer 12 isformed with several exposure holes 120 for exposing correspondingelectrodes 101,111. Each of the exposure holes 120 is formed inside withan electrically conductive linker 13 for electrically connecting theelectrodes 101,111 to external circuit components (not shown). Each ofthe electrically conductive linker 13 can be made of four metal layers,such as a combination of a chromium layer, a copper layer, a nickellayer and a gold layer, a combination of a silver layer, a copper layer,a nickel layer and a gold layer, or a combination of a chromium layer, adiamond-graphite film layer, a copper layer and a tin layer.

It should be noted that the insulation layer 12 is made of aphotosensitive material, preferably a transparent photosensitivematerial doped with phosphor powder.

Next, a generally basin-shaped rectangular accommodating housing 2 isprovided, which is made of insulative transparent material doped withphosphor powder. The housing 2 can be manufactured by any suitableprocess, such as by a molding process, so as to have an open end throughwhich a plurality of equal sized accommodating spaces 20 are accessible.

It should be understood that the phosphor powder doped in the materialsthat constitute the insulation layer 12 and the housing 2 may beindependently a phosphor powder of any color or any combination ofcolors, depending on actual need.

The LED die, which is provided with electrically conductive linkers 13as shown in FIG. 1, is positioned within a corresponding accommodatingspace 20 of the housing 2 in such a manner that the electricallyconductive linker 13 protrudes outwardly from the accommodating space20. The LED die provided with electrically conductive linkers 13 can besecured within the accommodating space 20 by any suitable process.According to this embodiment, the LED die is fixed to the accommodatingspace 20 by applying a transparent adhesive layer (not shown) betweenthe LED die and inner walls of the accommodating space 20.

After the respective LED dies are placed into the accommodating spaces20 corresponding thereto, the housing 2 is subjected to a dicingprocess, so as to obtain an LED die package 1 covered with a phosphorlayer 2′ as shown in FIG. 5. Since the respective phosphor layers 2′ ofthe LED dies packages 1 are of the same shape and thickness, thephosphor powder will generate light with the same color temperature andbrightness by being excited by the blue light emitted from the LEDchips. Therefore, the conventional problem of producing 40% side binscaused by application of phosphor powder during the LED packagingprocess is solved. Moreover, the position of the phosphor layer 2′relative to the LED chip will not offset. The invention effectivelyovercomes the drawbacks present in the conventional LED packagesaccordingly.

It should be noted that the housing 2 may be diced during the dicingprocess in such manner that a single LED die package contains aplurality of LED dies.

FIG. 7 is a schematic top partial view of a printed circuit board onwhich an LED die package provided with a plurality of LED dies ismounted.

As shown in FIG. 7, the electrically conductive linkers 13 of the LEDdies of the LED die package are electrically connected in series onamounting surface of a printed circuit board 3 by being electricallyconnected to a predetermined circuit trace 30 formed beforehand on themounting surface of the printed circuit board 3. Each of the LED dies iselectrically connected in parallel to a fuse unit 4 made of SiOH₄. Whenan LED die fails to work normally and causes an open circuit, the fuseunit 4 corresponding thereto melts down due to overvoltage and istherefore short-circuited to turn into an electrically connected state.Hence, even if one of the LED dies connected in series fails to functionnormally, the rest of them would remain operating. The conventionalproblem in this respect is overcome accordingly.

It should be noted that the circuit trace 30 can be formed by applyingan electrically conductive adhesive, such as a silver paste, or byplating copper onto the board. While FIG. 7 shows a printed circuitboard on which an LED die package provided with a plurality of LED diesis mounted, it should be understood that an LED die package containsonly a single LED die as shown in FIG. 6 can be mounted onto a printedcircuit board by a similar manner to that described above.

Preferably, the amount of the LED dies connected in series as shown inFIG. 7 is from 2 to 48 in the case where the incoming power of 110V ACis converted to 156V DC, or from 49 to 90 in the case where the incomingpower of 220V AC is converted to 360V DC.

Now referring to FIG. 10, it shows an LED die package according toanother preferred embodiment of the invention. Contrary to the firstpreferred embodiment, this embodiment is featured by forming a bufferlayer 5 on the surfaces 100, 110 of the first doped layer 10 and thesecond doped layer 11, before the formation of the insulation layer 12.The buffer layer 5 is then subjected to exposure and developmentprocesses to form through holes 50 for exposing corresponding solderpads 101,111. The insulation layer 12 is then disposed on the bufferlayer 5 and, by being subjected to exposure and development processes,formed with several exposure holes 120 registered with the correspondingthrough holes 50 and a via hole 121 for exposing a portion of the bufferlayer 5 that is located between the through holes 50. Then, the throughholes 50 and the exposure holes 120 are each formed inside with anelectrically conductive linker 13 for electrically connecting theelectrodes 101,111 to external circuit components (not shown). Each ofthe electrically conductive linker 13 is preferably made of four metallayers, such as a combination of a chromium layer, a copper layer, anickel layer and a gold layer, a combination of a silver layer, a copperlayer, a nickel layer and a gold layer, or a combination of a chromiumlayer, a diamond-graphite film layer, a copper layer and a tin layer. Itcan been seen from FIG. 10 that the via hole 121 is formed inside withan electrically conductive linker 13. However, the electricallyconductive linker 13 is provided within the via hole 121 for heatdissipation, rather than for connection to external circuit components.

The buffer layer 5 is provided for the purpose of buffering the stressthat occurs between a thin silicon oxide layer (not shown) formed on thesurfaces 100, 110 of the doped layers 10, 11 and the heat-dissipatingconductor 13 located within the through holes 50.

In conclusion, the LED die package and the method for producing the sameas disclosed herein can surely achieve the intended objects and effectsof the invention by virtue of the structural arrangements and operatingsteps described above.

While the invention has been described with reference to the preferredembodiments above, it should be recognized that the preferredembodiments are given for the purpose of illustration only and are notintended to limit the scope of the present invention and that variousmodifications and changes, which will be apparent to those skilled inthe relevant art, may be made without departing from the spirit of theinvention and the scope thereof as defined in the appended claims.

What is claimed is:
 1. A light-emitting diode die package, comprising: alight-emitting diode die having a first doped layer doped with a p- orn-type dopant and a second doped layer doped with a different dopantfrom that doped in the first doped layer and disposed on the first dopedlayer, wherein each of the second doped layer and the first doped layerhas an electrode-forming surface formed with an electrode, on which abuffer layer is formed, and wherein the buffer layer is formed with aplurality of through holes for exposing the electrodes correspondingthereto; an insulation layer formed on the buffer layer, wherein theinsulation layer is formed with a plurality of exposure holes, eachbeing registered with the through holes corresponding thereto, and atleast one via hole for exposing a portion of the buffer layer that isexposed by the through holes, and wherein the through holes and theexposure holes are each formed inside with an electrically conductivelinker; and a generally basin-shaped rectangular accommodating housingmade of an insulative transparent material doped with phosphor powder,the housing having an open end through which an accommodating space isaccessible, wherein the light-emitting diode die is positioned withinthe accommodating space of the housing in such a manner that theelectrically conductive linker protrudes outwardly from theaccommodating space.